In reply to steronz: Like someone else mentioned, drive someone else's well sorted Miata. The stock suspension is terrible; see if a good one is good enough for you, or you need to sell your Miata to one of us 
and buy something you like and fit into better. I would go with a Corbea/Sparco/Recaro sport or racing seat, they are shaped better and are lower (the racing ones, anyway) than the stock seats.
I'm 6'1" and I don't fit in them either. Also, one of my fellow autocrossers is 6'5", and he cut the floor and lowered it an inch or two, and put in Corbeau racing seats in it. Drastic measures can be done. 
UH-HUM......some of us here are the proper size 5' 7" 140lbs and do notice that folks whose physique might be better suited to basketball or football still manage to shoehorn themselves in.
I'd be looking at either a custom bar or one that bolted in and out easily for track days.
As for the cornering on the bump stops; my 90 showroom stock C race car did this but it wasn't really an issue. The only place it ever became an issue was a banked corner with a bump on the exit.
As for the floppy nature of a the stock suspension; in the aforementioned 90 SSC Miata on the Las Vegas Motor Speedway outside road course turn one might give some people pause. I'd turn in flat it about 100-103 mph, I'd turn the steering wheel 90 degrees than a split second later (after the outside suspension compressed) the car would hook down into the corner. The first time I drove the car I was susprised at how after a 3 laps this seemed perfectly normal. Even with the body roll the balance was flawless. The fast set up on the car also seemed to be slightly worn rear shocks, not pogoing wildly, but still a bit soft.
I mention the delayed reaction above because if you are coming from a overly stiff car with snappy feedback then yes a stock Miata might feel disconcerting. I also mention the overly stiff suspension because while this gives an instantaneous feedback very often it results in a car that builds less lateral than it could. It does sound like the car here has worn out dampers.
Like someone else mentioned Spec Miatas run some pretty stiff springs yet they are pretty compliant.
I had a first generation MR2 that was well set up and didn't really like it in comparison to the Miata........horses for courses.
Tom
